Covering just 6% of the earth’s surface, wetlands are vital for human survival. While wetlands are well-known for their critical role in supporting biodiversity, they also play an equally vital, though overlooked, role in regulating air quality and the climate. However, rising air pollution and climate change are putting wetlands under increasing pressure, threatening their ability to filter pollutants, store carbon, and sustain biodiversity.
On World Wetlands Day, Air Aware Labs celebrates these ecosystems for their far-reaching contributions beyond water systems. They are among the most biodiverse and biologically productive ecosystems in the world, encompassing swamps, marshes, bogs and areas periodically covered by water - housing 40% of all plant and animal species. They provide food and shelter for plants and animals, while also acting as natural barriers against flooding, erosion and particles.
Wetlands are known for the crucial role they have in the water cycle by absorbing water, slowing the momentum of water flow, and mitigating coastal storm surge. Their root systems anchor them in place, and filter out pollutants, improving water quality. As the levels of air pollution rise, so does the risk to our health and environment. Protecting wetlands means safeguarding the air we breathe and the ecosystems that sustain us.
Wetlands and the Air
Wetlands act as natural filters to particulate matter. They trap sediment, remove pollutants, and detoxify the chemicals in the water that come from agricultural lands, roads, industrial sites, or developed areas. Wetlands can remove up to 60% of metals, retain up to 90% of sediment runoff, and eliminate up to 90% of nitrogen. They therefore play a key role in reducing air pollution concentrations in urban areas.
In addition to their filtering abilities, wetlands serve as powerful carbon sinks, storing an incredible 35% of global terrestrial carbon, preventing its release into the atmosphere. In the United States alone, terrestrial wetlands absorb 13.5 billion tons of carbon. However, when wetlands are disturbed, they can release carbon dioxide, methane and nitrous oxide into the atmosphere, further exacerbating climate change.
Threats to Wetlands
Wetlands face increasing threats from air pollution and climate change. Their role as natural "collectors" of pollutants makes them particularly vulnerable. The buildup of pollution degrades water quality and causes the health of the wetland to be at risk. Only 14% of the UK’s rivers meet European ecological health standards, whilst globally, an estimated 8 to 12 million tons of plastic finds its way into oceans every year.
Nitrogen deposition poses a serious threat to wetland ecosystems, with levels as low as 10 kg per hectare per year causing significant changes in species composition and key ecosystem functions such as canopy height, specific leaf area, and nitrogen availability. Certain wetlands, such as minerotrophic fens, thrive in nutrient-poor, but base-rich conditions. These ecosystems are home to small sedges and brown mosses; however, excess nitrogen in the atmosphere accelerates the growth of grass and eventually tree species, outcompeting and displacing species such as bryophytes and lichens. In addition to nitrogen deposition, sources such as nitrate leaching from agricultural land, along with urban and transport activities (emitting excess nitrogen dioxide) cause the degradation of water quality. These sources of pollution significantly impact the ecological health of wetlands, reducing biodiversity and threatening long-term stability.
Ground-level ozone pollution presents another significant threat to wetland habitats. Mosses, lichens, and other plants in wetlands are particularly vulnerable to ozone due to their high stomatal conductance, which increases ozone absorption. The UK wetlands are less prone to water shortages which means they are more susceptible to the harmful effects of ozone.
Fertilisers and pesticides used in agriculture further degrade wetlands by harming animals and plants, weakening the ecosystem’s ability to function as an effective carbon sink. The cumulative impact of these pollutants undermines the health and biodiversity of wetlands.
Wetlands and Air Aware Labs
Protecting wetlands means safeguarding the air we breathe, the water we drink, and the ecosystems that sustain life. As we celebrate World Wetlands Day, Air Aware Labs recognises how they provide natural barriers to air pollution, effective carbon sinks, and vital regulators of greenhouse gas emissions. However, rising pollution levels, nitrogen deposition and climate change put these critical ecosystems at risk. Air Aware Labs supports the protection of wetlands which are essential for preserving cleaner air and a healthier future. By safeguarding these remarkable ecosystems from exposure to air pollution, we protect the planet and ourselves.
By Abigail Manthous, overseen by Dr Will Hicks
